Molecular and General Genetics MGG

, Volume 230, Issue 1–2, pp 155–160

Demonstration of nucleomorph-encoded eukaryotic small subunit ribosomal RNA in cryptomonads

  • Uwe -G. Maier
  • Claudia J. B. Hofmann
  • Stefan Eschbach
  • Jörn Wolters
  • Gabor L. Igloi


In cryptomonads, unicellular phototrophic flagellates, the plastid(s) is (are) located in a special narrow compartment which is bordered by two membranes; it harbours neither mitochondria nor Golgi dictyosomes but comprises eukaryotic ribosomes and starch grains together with a small organelle called the nucleomorph. The nucleomorph contains DNA and is surrounded by a double membrane with pores. It is thought to be the vestigial nucleus of a phototrophic eukaryotic endosymbiont. Cryptomonads are therefore supposed to represent an intermediate state in the evolution of complex plastids from endosymbionts. We have succeeded in isolating pure nucleomorph fractions, and can thus provide, using pulsed field gel electrophoresis, polymerase chain reaction and sequence analysis, definitive proof for the eukaryotic nature of the symbiont and its phylogenetic origin.

Key words

Cryptomonads Nucleomorph Small subunit ribosomal RNA 


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Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • Uwe -G. Maier
    • 1
  • Claudia J. B. Hofmann
    • 1
  • Stefan Eschbach
    • 1
  • Jörn Wolters
    • 2
  • Gabor L. Igloi
    • 3
  1. 1.Institut für Biologie II, ZellbiologieUniversität FreiburgFreiburgGermany
  2. 2.Institut für Allgemeine MikrobiologieKiel 1Germany
  3. 3.Institut für Biologie IIIFreiburgFRG

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